The background of the invention is illustrated with the example of NPN transistor. Current bipolar transistor's structure is shown as FIG. 1 including collector 114, base 111 and emitter 110. Collector 114 is N− epitaxial layer grown on N+ buried layer 102, Collector area is picked up by N-type heavy doped buried layer 102 on substrate 102, N-type high doped collector pick-up 104 in active area, deep contact 106 in interlayer dielectric (ILD) 105 and metal electrode 107. N-type high doped collector pick-up 104 is formed by high dose and high energy implant. Collector 114 is isolated by shallow trench isolation (STI) 103. Between transistors, there is a deep trench 115 filled with polysilicon on the bottom of STI to reduce the parasitic capacitor of collector/substrate and improve transistor frequency performance. Base 111 is a in-situ P-type doped epitaxial layer and is picked up by poly layer 108 above oxide dielectric 113. Emitter 110 is N-type heavy doping polysilicon layer on base 111. Emitter 110 is surrounded by oxide sidewall 112. Emitter 110 touches base 111 directly by emitter window in oxide 109. Local collector implants can be done through emitter window to adjust transistor's breakdown voltage and cutoff frequency. In current process, in order to increase breakdown voltage of HV transistors, collector epitaxial thickness needs to be increased to enlarge depletion width of collector/base junction. As the result, the process cost is high, also high frequency and high voltage bipolar transistors are hard to be integrated.